From 93efbde2c331004d8053f04b4bf0ca3e630b474a Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Wed, 20 Nov 2019 22:12:38 -0800 Subject: x86/traps: Disentangle the 32-bit and 64-bit doublefault code The 64-bit doublefault handler is much nicer than the 32-bit one. As a first step toward unifying them, make the 64-bit handler self-contained. This should have no effect no functional effect except in the odd case of x86_64 with CONFIG_DOUBLEFAULT=n in which case it will change the logging a bit. This also gets rid of CONFIG_DOUBLEFAULT configurability on 64-bit kernels. It didn't do anything useful -- CONFIG_DOUBLEFAULT=n didn't actually disable doublefault handling on x86_64. Signed-off-by: Andy Lutomirski Cc: Borislav Petkov Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Linus Torvalds Signed-off-by: Ingo Molnar --- arch/x86/Kconfig.debug | 2 +- arch/x86/include/asm/processor.h | 1 - arch/x86/kernel/doublefault.c | 11 ----------- arch/x86/kernel/traps.c | 12 +++--------- 4 files changed, 4 insertions(+), 22 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug index 409c00f74e60..c4eab8ed33a3 100644 --- a/arch/x86/Kconfig.debug +++ b/arch/x86/Kconfig.debug @@ -117,7 +117,7 @@ config DEBUG_WX config DOUBLEFAULT default y - bool "Enable doublefault exception handler" if EXPERT + bool "Enable doublefault exception handler" if EXPERT && X86_32 ---help--- This option allows trapping of rare doublefault exceptions that would otherwise cause a system to silently reboot. Disabling this diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index e51afbb0cbfb..f6c630097d9f 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -997,7 +997,6 @@ bool xen_set_default_idle(void); #endif void stop_this_cpu(void *dummy); -void df_debug(struct pt_regs *regs, long error_code); void microcode_check(void); enum l1tf_mitigations { diff --git a/arch/x86/kernel/doublefault.c b/arch/x86/kernel/doublefault.c index 0d6c657593f8..0b3c616b61a3 100644 --- a/arch/x86/kernel/doublefault.c +++ b/arch/x86/kernel/doublefault.c @@ -72,15 +72,4 @@ struct x86_hw_tss doublefault_tss __cacheline_aligned = { .__cr3 = __pa_nodebug(swapper_pg_dir), }; -/* dummy for do_double_fault() call */ -void df_debug(struct pt_regs *regs, long error_code) {} - -#else /* !CONFIG_X86_32 */ - -void df_debug(struct pt_regs *regs, long error_code) -{ - pr_emerg("PANIC: double fault, error_code: 0x%lx\n", error_code); - show_regs(regs); - panic("Machine halted."); -} #endif diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index c90312146da0..76381b04dc93 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -411,15 +411,9 @@ dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code, unsign handle_stack_overflow("kernel stack overflow (double-fault)", regs, cr2); #endif -#ifdef CONFIG_DOUBLEFAULT - df_debug(regs, error_code); -#endif - /* - * This is always a kernel trap and never fixable (and thus must - * never return). - */ - for (;;) - die(str, regs, error_code); + pr_emerg("PANIC: double fault, error_code: 0x%lx\n", error_code); + show_regs(regs); + panic("Machine halted."); } #endif -- cgit